CYTOMETRY 2012—What would Ehrlich do?

Abstract

CYTO 2012, the 27th Congress of the International Society for Advancement of Cytometry (ISAC), finds us in Leipzig, a city with deep roots in science, industry, and the arts. Leipzig was an artistic home to Bach, Mendelsohn, and Goethe and sites featured in their lives and work can be found throughout the city center. Leipzig is also an historic center for trade, founded at the crossing of two ancient trade routes, Via Regia and Via Imperii, and has served as a major market town for nearly 1,000 years. Trade activities shaped the architecture of the courtyards and passageways of the city center and, in more recent times, the Congress Centre Leipzig, the venue of CYTO 2012. Finally, Leipzig holds a special distinction as a home to the very roots of cytometry. Paul Ehrlich received his medical degree from the University of Leipzig in 1878, after writing a dissertation on ‘‘Contributions to the Theory and Practice of Histological Staining.’’ His supervisor Julius Friedrich Cohnheim was the inventor of intra-vital microscopy. Strongly influenced by his cousin Karl Weigert, a great microscopist in his own right and an assistant to the preeminent pathologist Rudolf Virchow, Ehrlich made use of aniline dyes to identify different cell types in blood by the staining patterns of their organelles after treatment with mixtures of acidic and basic dyes, discovering the Mast cells. The dye industry itself was then driven primarily by the needs of fashion, having originated in the 1850s with the serendipitous synthesis of mauve in London by William Perkin in a failed attempt to produce quinine, an expensive natural product then the only available treatment for malaria. The stains used in hematologic microscopy and malaria diagnosis today are but a few steps removed from Ehrlich’s eosin–methylene blue mixtures [recently used for in vivo flow cytometry (1)]; his ‘‘acid-fast’’ staining procedure for Mycobacterium tuberculosis and related bacterial species is similarly close to today’s venerable Ziehl–Neelsen and auramine O stains for TB, and Ehrlich’s work inspired Hans Christian Gram to develop his own well-known stain for bacteria.